Department of Chemistry─BMC, Uppsala University, 75123 Uppsala, Sweden.
Department of Medical Cell Biology, Uppsala University, 75123 Uppsala, Sweden.
Anal Chem. 2022 Sep 20;94(37):12875-12883. doi: 10.1021/acs.analchem.2c02918. Epub 2022 Sep 7.
Targeted and nontargeted metabolomics has the potential to evaluate and detect global metabolite changes in biological systems. Direct infusion mass spectrometric analysis enables detection of all ionizable small molecules, thus simultaneously providing information on both metabolites and lipids in chemically complex samples. However, to unravel the heterogeneity of the metabolic status of cells in culture and tissue a low number of cells per sample should be analyzed with high sensitivity, which requires low sample volumes. Here, we present the design and characterization of the direct infusion probe, DIP. The DIP is simple to build and position directly in front of a mass spectrometer for rapid metabolomics of chemically complex biological samples using pneumatically assisted electrospray ionization at 1 μL/min flow rate. The resulting data is acquired in a square wave profile with minimal carryover between samples that enhances throughput and enables several minutes of uniform MS signal from 5 μL sample volumes. The DIP was applied to study the intracellular metabolism of insulin secreting INS-1 cells and the results show that exposure to 20 mM glucose for 15 min significantly alters the abundance of several small metabolites, amino acids, and lipids.
靶向和非靶向代谢组学有可能评估和检测生物系统中的全局代谢物变化。直接进样质谱分析能够检测所有可电离的小分子，从而同时提供化学复杂样品中代谢物和脂质的信息。然而，为了揭示培养细胞和组织中代谢状态的异质性，每个样本应该用高灵敏度分析少量细胞，这需要小体积的样本。在这里，我们提出了直接进样探针（DIP）的设计和表征。DIP 构建简单，可直接置于质谱仪前，以 1 μL/min 的流速通过气动辅助电喷雾离子化快速进行化学复杂生物样品的代谢组学分析。所得数据以方波轮廓采集，样品之间的交叉污染最小，提高了通量，并使 5 μL 样品体积的均匀 MS 信号持续几分钟。该 DIP 用于研究胰岛素分泌 INS-1 细胞的细胞内代谢，结果表明，暴露于 20 mM 葡萄糖 15 分钟会显著改变几种小分子、氨基酸和脂质的丰度。
